The present invention relates generally to control valves or devices used to start or stop the flow of liquids and more particularly to control valves designed to start or stop the flow of a liquid after a predetermined time or, in the case of stopping the flow of a liquid, after a predetermined amount of liquid has flowed through the valve.
Automatic control valves are known which stop the flow of liquid after a predetermined amount of liquid has been delivered. For example, such valves are designed to permit filling of tanks with liquids and to automatically shut off after a certain number of gallons have been delivered. These valves avoid the necessity of having someone present to visually observe the filling of the tank and manually turn the flow off thereby preventing overflowing.
Flow control valves designed to automatically shut off the flow of a liquid after a predetermined period of time are also known in the art. See, for example, U.S. Pat. No. 2, 769,574, issued Nov. 6, 1956 and U.S. Pat. No. 3,089,651, issued May 14, 1963. The known valves are relatively complicated in structure and have many moving parts. A number of them require an external mechanical or electrical timing device. Such complex valves may tend to malfunction and not stop the liquid flow as desired.
It is common knowledge that many resources which have heretofore been considered plentiful are actually limited in availability and should be conserved to the extent possible. Water is one of these limited resources. Recent water shortages in various areas of the United States have led to major efforts to conserve water. In many parts of the United States it is no longer possible to use as much water as one might like. For example, many communities permit watering of one's lawn or garden only during certain periods of time. Excess watering is considered wasteful and no longer allowed in some localities. In addition, only non-peak time (e.g. nighttime) watering is allowed in some localities.